1. Field of Invention
The present invention relates to a power plane and a manufacturing method thereof. More particularly, the present invention relates to a power plane and the manufacturing method which is able to filter out resonant high frequency noises.
2. Description of Related Art
In high-speed digital circuits, plane noises are generated when high-speed signals pass through an non-ideal path, such as the via or a discontinuous reference plane. The plane noises might propagate to other positions between planes of digital circuit board in a parallel-plate waveguide form.
To prevent plane noises interfering with the electronic components on the digital circuit, the power plane of the digital circuit is initially divided into at least two parts in the beginning, then the decoupling capacitance or the inductor may be added between the divided power planes for filtering out the noises traditionally.
Although dividing the power plane into several parts can filter out the low frequency noises, the resonant high frequency noises can not be filtered out, yet. The remaining high frequency noises might make the signals which are passed on the power plane imperfect, or interfere with the electronic components on the digital circuit.
For the foregoing reasons, there is a need for a new power plane and a manufacturing method thereof, which effectively filters out the resonant high frequency noises.